docs: def input_list_parser(infile_list):
      """Always return a list of files with varying input.
  
      >>> input_list_parser(['/path/to/folder/'])
      ['/path/to/folder/file1.txt', '/path/to/folder/file2.txt', '/path/to/folder/file3.txt']
  
      >>> input_list_parser(['/path/to/file.txt'])
      ['/path/to/file.txt']
  
      >>> input_list_parser(['file1.txt'])
      ['file1.txt']
  
      Args:
          infile_list: List of arguments
  
      Returns:
          list: Standardized list of files
  
      """
  
      final_list_of_files = []
  
      for x in infile_list:
  
          # If the input is a folder
          if op.isdir(x):
              os.chdir(x)
              final_list_of_files.extend(glob.glob('*'))
  
          # If the input is a file
          if op.isfile(x):
              final_list_of_files.append(x)
  
      return final_list_of_files